When you squeeze the bag of frosting, Pascal's law states that the pressure will be transmitted equally in all directions throughout the frosting. This means that the frosting will be forced out of the tip of the bag with the same amount of pressure as you apply on the bag. The amount of frosting that comes out will depend on the size of the opening of the tip and the amount of pressure you apply on the bag. If you apply more pressure, the frosting will come out more quickly and if you apply less pressure, the frosting will come out more slowly.